1. Field of the Invention
This invention relates generally to the field of treating wells to stimulate fluid production. More particularly, the invention relates to the field of combining the use of downhole tools with the use of abrasive jet perforating tools in a single trip in a well.
2. Description of the Related Art
Abrasive jet perforating uses fluid slurry pumped under high pressure to perforate tubular goods around a wellbore, where the tubular goods include tubing, casing, and cement. Since sand is the most common abrasive used, this technique is also known as sand jet perforating (SJP). Abrasive jet perforating was originally used to extend a cavity into the surrounding reservoir to stimulate fluid production. It was soon discovered, however, that abrasive jet perforating could not only perforate, but cut (completely sever) the tubular goods into two pieces. Sand laden fluids were first used to cut well casing in 1939. Abrasive jet perforating was eventually attempted on a commercial scale in the 1960s. While abrasive jet perforating was a technical success (over 5,000 wells were treated), it was not an economic success. The tool life in abrasive jet perforating was measured in only minutes and fluid pressures high enough to cut casing were difficult to maintain with pumps available at the time. A competing technology, explosive shape charge perforators, emerged at this time and offered less expensive perforating options.
Consequently, very little work was performed with abrasive jet perforating technology until the late 1990's. Then, more abrasive-resistant materials used in the construction of the perforating tools and jet orifices provided longer tool life, measured in hours or days instead of minutes. Also, advancements in pump materials and technology enabled pumps to handle the abrasive fluids under high pressures for longer periods of time. The combination of these advances made the abrasive jet perforating process more cost effective. Additionally, the recent use of coiled tubing to convey the abrasive jet perforating tool down a wellbore has led to reduced run time at greater depth. Further, abrasive jet perforating did not require explosives and thus avoids the accompanying danger involved in the storage, transport, and use of explosives. However, the basic design of abrasive jet perforating tools used today has not changed significantly from those used in the 1960's.
Abrasive jet perforating tools and casing cutters were initially designed and built in the 1960's. There were many variables involved in the design of these tools. Some tool designs varied the number of jet locations on the tool body, from as few as two jets to as many as 12 jets. The tool designs also varied the placement of those jets, such, for example, positioning two opposing jets spaced 180° apart on the same horizontal plane, three jets spaced 120° apart on the same horizontal plane, or three jets offset vertically by 30°. Other tool designs manipulated the jet by orienting it at an angle other than perpendicular to the casing or by allowing the jet to move toward the casing when fluid pressure was applied to the tool.
As abrasive jet perforating use increases, the desire to combine it with other steps in the well completion, stimulation, and intervention processes also increase. Having the ability to selectively close flow below a tool like an abrasive jet perforator, perform perforations, then resume flow through that section of the bottomhole tool assembly allows other tasks like milling to be performed while also completing the abrasive jet perforating job in the same trip. This combination reduces the number of trips in and out of the well, which, in turn lowers completion costs.
The following patents and publications are representative of conventional abrasive jet perforating tools, along with apparatuses and methods that may be employed with the tools.
U.S. Pat. No. 3,066,735 by Zingg, “Hydraulic Jetting Tool”, discloses the use of drop balls and a sliding cylinder or sleeve to block jet orifices and to switch fluid flow between jets in an abrasive jet perforating tool.
U.S. Pat. No. 3,130,786, by Brown et al., “Perforating Apparatus”, discloses sealing off the bottom of the abrasive jet perforating tool with a ball valve to allow pressure to increase for the abrasive jet perforating job.
U.S. Pat. No. 3,266,571 by St. John et al., “Casing Slotting” discloses an abrasive jet perforating tool designed to cut slots of controlled length. The slot lengths are controlled by abrasive resistant shields attached to the tool to block the flow from rotating abrasive jets.
U.S. Pat. No. 5,533,571 by Surjaatmadj a et al., “Surface Switchable Down-Jet/Side-Jet Apparatus”, discloses a sliding valve sleeve activated by a dropped ball that, when pressure is applied, forces the valve sleeve to shear a shear pin. In a first position, jetting is out a longitudinally directed port. In a second position, jetting is out a transverse port.
U.S. Pat. No. 6,085,843 by Edwards et al., “Mechanical Shut-Off Valve”, discloses a shut-off valve connecting adjacent tools in a downhole string, permitting or blocking hydraulic or ballistic communication.
U.S. Pat. No. 8,066,059 B2, by Ferguson et al., “Method and Devices for One Trip Plugging and Perforating of Oil and Gas Wells”, discloses an abrasive jet perforating tool that uses sliding sleeves to permit fluid flow through the perforating tool to a bridge plug. Setting the bridge plug directs abrasive fluid flow to the perforating orifices.
An SPE publication by J. S. Cobbett, “Sand Jet Perforating Revisited”, SPE 55044, SPE Drill. & Completion, Vol. 14, No. 1, p. 28-33, March 1999, discloses the use of sand jet perforating (abrasive jet perforating) with coiled tubing to increase production in damaged wells, using examples of neglected wells in Lithuania.
Thus, a need exists for a flow isolation tool assembly and a method of use that allows fluid flow through an inner diameter of an assembly of downhole tools in a well, then selectively blocks the fluid flow at a desired location in the assembly of tools, and finally allows re-establishment of fluid flow through the tools again after the desired task is complete.